Constant velocity joint having fixed center and crossed grooves

ABSTRACT

A constant velocity counter track joint having an outer joint part with outer ball tracks having first tracks opening toward the aperture end and second tracks opening toward the attaching end. The center line of the second tracks, in departs, radially inwardly, a first reference radius centered in the point of intersection of a perpendicular line on the tangent at the center line of the ball track and the longitudinal axis. In the inner joint part, the center line of the ball tracks departs, radially inwardly, a second reference radius centered in the point of intersection of a perpendicular line on the tangent at the center line of the ball track and the longitudinal axis. In the outer joint part, the center line of the ball tracks towards the aperture ends moves radially outwardly beyond said first reference radius. In the inner joint part, the center line of the ball tracks towards the attaching ends, moves radially outwardly beyond said second reference radius.

The invention relates to a constant velocity joint in the form of acounter track joint with the following characteristics: an outer jointpart which comprises a longitudinal axis L12 and an attaching end and anaperture end arranged so as to be axially opposite one another, andwhich is provided with outer ball tracks,

an inner joint part which comprises a longitudinal axis L13 andattaching means for a shaft pointing towards the aperture end of theouter joint part, and which is provided with inner ball tracks,

the outer ball tracks and the inner ball tracks form pairs of trackswith one another,

the pairs of tracks each accommodate a torque transmitting ball,

an annular ball cage is positioned between the outer joint part and theinner joint part and comprises circumferentially distributed cagewindows which each accommodate at least one of the torque transmittingballs,

the centres of the balls are held by the cage in a joint centre plane EMand, upon articulation of the joint, are guided onto the angle-bisectingplane between the longitudinal axes L12, L13,

for a first part of the pairs of tracks, the opening angle α₁ betweenthe tangents T22 ₁′, T23 ₁′ at track base lines extending parallel tothe tangents T22 ₁, T23 ₁ at the centre lines M22 ₁, M23 ₁ of the balltracks in the joint centre plane EM when the joint is in the alignedcondition with coinciding longitudinal axes L12, L13, opens from theattaching end to the aperture end, for a second part of the pairs oftracks, the opening angle α₂ between the tangents T22 ₂′, T23 ₂ ¹′ attrack base lines extending parallel to the tangents T22 ₂, T23 ₂ at thecentre lines of the ball tracks in the joint centre plane when the jointis in the aligned condition with coinciding longitudinal axes L12, L13opens from the aperture end to the attaching end. With reference to thejoint centre plane EM, the centre lines of pairs of tracks aresubstantially mirror-image like relative to one another.

Prior art counter track joints comprise an even number of pairs oftracks. The first half of said pairs of tracks opens towards theaperture end of the outer joint part. The other half of said pairs oftracks opens towards the attaching end of the outer joint part. Thepairs of tracks of the first type and second type are arranged so as toalternate if viewed in the circumferential direction. The tracks arearranged on meridian planes R which, in the circumferential direction,comprise uniform pitch angles of 360°/n, with n being the number ofpairs of tracks, e.g. 6, 8, 10.

The alternating pairs of tracks are curved in such a way that, in thejoint centre plane EM, they comprise a tangent angle α₁, α₂ at the trackbase lines, which angles are identical in size, but differ in respect oforientation, and the track extensions of the alternating pairs of tracksare mirrored with reference to the joint centre plane. Prior art countertrack joints permit only a relatively small articulation angle of 35°,which is due to the pairs of tracks opening towards the attaching end ofthe outer joint part and closing towards the aperture end and having tobe relatively short towards the aperture end to allow the cage to bemounted in the outer joint part.

DE 100 60 220 A1 proposes counter track joints wherein the second pairsof tracks are provided with different track shapes which also includetrack centre lines extending in an S-shaped way and having a turningpoint in the outer joint part and in the inner joint part. The trackcentre lines are defined as being the path of the centres of the ballsin the ball tracks.

It is the object of the present invention to provide fixed joints of theabove-described type with increased articulation angles.

A first solution consists in providing a constant velocity joint in theform of a counter track joint with the following characteristics:

an outer joint part which comprises a longitudinal axis L12 and anattaching end and an aperture end arranged so as to be axially oppositeone another, and which is provided with outer ball tracks,

an inner joint part which comprises a longitudinal axis L13 andattaching means for a shaft pointing towards the aperture end of theouter joint part, and which is provided with inner ball tracks

the outer ball tracks and the inner ball tracks form pairs of trackswith one another,

the pairs of tracks each accommodate a torque transmitting ball,

an annular ball cage is positioned between the outer joint part and theinner joint part and comprises circumferentially distributed cagewindows which each accommodate at least one of the torque transmittingballs,

the centres of the balls are held by the cage in a joint centre planeand, upon articulation of the joint, are guided onto the angle-bisectingplane between the longitudinal axes, the centre lines M22, M23 of theball tracks of pairs of tracks are positioned in radial planes R throughthe joint, for a first part of the pairs of tracks, the opening angle α₁between the tangents T22 ₁ ¹′, T23 ₁′ at track base lines extendingparallel to the tangents T22 ₁, T23 ₁ at the centre lines M22 ₁, M23 ₁of the ball tracks in the joint centre plane EM when the joint is in thealigned condition with coinciding longitudinal axes L12, L13 opens fromthe attaching end to the aperture end,

for a second part of the pairs of tracks, the opening angle α₂ betweenthe tangents T22 ₂′, T23 ₂ ¹′ at track base lines extending parallel tothe tangents T22 ₂, T23 ₂ at the centre lines M22 ₂, M23 ₂ of the balltracks 22 ₂, 23 ₂ in the joint centre plane EM when the joint is in thealigned condition with coinciding longitudinal axes L12, L13 opens fromthe aperture end to the attaching end, and the following applies to thecentre lines of the second pairs of tracks;

in the outer joint part, the centre line M22 ₂ of the ball tracks in theregion from the joint centre plane EM to the attaching end radiallyinwardly leaves a reference radius RB whose radius centre MB ispositioned in the point of intersection of a perpendicular line on thetangent T22 ₂′ at the centre line M22 ₂ of the ball track in the jointcentre plane EM and of the longitudinal axis L12,

in the inner joint part, the centre line M23 ₂ of the ball tracks in theregion from the joint centre plane EM to the aperture end radiallyinwardly leaves a reference radius RB′ whose radius centre MB′ ispositioned in the point of intersection of a perpendicular line on thetangent T23 ₂′ at the centre line M23 ₂ of the ball track in the jointcentre plane EM and of the longitudinal axis (L13),

in the outer joint part, the centre line centre line M22 ₂ of the balltracks in the region from the joint centre plane EM to the aperture endmoves radially outwardly beyond said reference radius RB,

in the inner joint part, the centre line centre line M23 ₂ of the balltracks in the region from the joint centre plane EM to the attaching endmoves radially outwardly beyond said reference radius RB′.

The track shape given here permits the maximum articulation angle to beincreased relative to prior art track shapes. The characteristicmentioned first according to which the centre lines leave the referenceradii inwardly can start directly at the joint centre plane or even at alater stage, and it can behave so as to increase progressively. Thesecond characteristic mentioned according to which the centre lines moveoutwardly beyond the reference radius includes a direct outward movementaway from the reference radius as well as a later crossing of thereference radius and subsequent outward movement.

According to a preferred further embodiment, the constant velocity jointis provided with the following further characteristics of the secondpairs of tracks:

in the outer joint part, the local radius of curvature R1 of the centreline M22 ₂ in the joint centre plane EM is smaller than the referenceradius RB,

in the inner joint part, the local radius of curvature R1′ of the centreline M23 ₂ in the joint centre plane EM is smaller than the referenceradius RB′.

According to a preferred embodiment, the constant velocity joint isprovided with the following further characteristics of the second pairsof tracks:

in the outer joint part, the centre line M22 ₂ of the ball tracksextends from the joint centre plane EM to the attaching end radiallyoutside a reference radius RZ whose radius centre is positioned in thejoint centre M,

in the inner joint part, the centre line M23 ₂ of the ball tracksextends from the joint centre plane EM to the aperture end radiallyoutside a reference radius RZ′ whose radius centre is positioned in thejoint centre M.

A further advantageous embodiment refers to the following furthercharacteristics of the second pairs of tracks:

in the outer joint part, the centre line M22 ₂ of the ball tracksextends from the joint centre plane EM to the aperture end radiallyoutside a reference radius RB and,

in the inner joint part, the centre line M23 ₂ of the ball tracksextends from the joint centre plane EM to the attaching end radiallyoutside a reference radius RB′.

According to a further embodiment, the following further characteristicsare proposed:

in the outer joint part, the centre line M22 ₂ of the ball tracksextends from the joint centre plane EM to the aperture end radiallyinside a reference radius RZ around the joint centre M and

in the inner joint part, the centre line M23 ₂ of the ball tacks extendsfrom the joint centre plane EM to the attaching end radially inside areference radius RZ′ around the joint centre M.

According to a further embodiment, the following further characteristicsof the second ball tracks are proposed:

the centre lines M22 ₂, M23 ₂ of the outer ball tracks and inner balltracks each comprise at least two arched portions which are curved inopposite senses and which adjoin one another in a turning point,

the turning points W22 ₂ of the outer ball tracks are positioned at adistance from the centre plane EM towards the aperture end,

the turning points W23 ₂ of the inner ball tracks are positioned at adistance from the centre plane EM towards the attaching end,

the turning points W22 ₂, W23 ₂ are each positioned below a maximum ofthe distance of the centre lines M22 ₂, M23 ₂ from the longitudinal axesL12, L13.

A further embodiment comprises the following characteristics of thesecond pairs of tracks:

the track centre lines M22 ₂ of the outer ball tracks comprise a firstarch with the radius R1 whose centre M1 is offset by a first axialoffset O1 a from the centre plane EM of the joint towards the attachingend and by a first radial offset O1 r from the longitudinal axis L12outwardly towards the ball track and, in the region adjoining said arch,towards the attaching end, they comprise a second arch with the radiusR2 whose centre M2 is offset by a second axial offset O2 a from thecentre plane EM of the joint towards the aperture end and offsetoutwardly from the longitudinal axis L12 by a second radial offset Or2which is greater than the sum of the first radius RI and the firstradial offset O1 r.

the track centre lines M23 ₂ of the inner ball tracks comprise a firstarch with the radius R1′ whose centre M1′ is offset by a first axialoffset O1 a′ from the centre plane EM of the joint towards the apertureend and offset outwardly by a first radial offset O1 r′ from thelongitudinal axis L13 to the ball track and, in the region adjoiningsaid arch, towards the aperture end, they comprise a second arch withthe radius R2′ whose centre is offset by a second axial offset 02 a′from the centre plane EM of the joint towards the attaching end andoffset outwardly from the longitudinal axis L13 by a second radialoffset Or2′ which is greater than the sum of the first radius R1′ andthe first radial offset O1 r′.

More particularly, the following further characteristics of the secondpairs of tracks are proposed:

the radius of curvature of the centre lines M22 of the outer ball tracksdecreases in the extension from the centre plane EM to the attaching endand the radius of curvature of the centre line M23 of the inner balltracks decreases in the extension from the centre plane EM to theaperture end.

More particularly, the following further characteristics of the secondpairs of tracks are proposed:

the track centre lines M22 ₂ of the outer ball tracks comprise a thirdarch with the radius of curvature R3 which tangentially, while havingthe same sense of curvature, adjoins the first arch with the radius ofcurvature R1 and whose radius of curvature R3 is smaller than the radiusof curvature R2, and the track centre lines M23 ₂ of the inner balltracks comprise a third arch with the radius of curvature R3′ whichtangentially, while having the same sense of curvature, adjoins thefirst arch with the radius of curvature R1′ and whose radius ofcurvature R3′ is smaller than the radius of curvature R1′.

According to a further embodiment it is proposed that, in the secondpairs of tracks, along the extension of the centre line M22 ₂ of theouter ball tracks, towards the aperture end, the second arch is adjoinedby an axis-parallel straight line G3 and that, along the extension ofthe centre line of the inner all tracks M23 ₂, towards the attachingend, the second arch is adjoined by an axis-parallel straight line G3′.

According to an alternative embodiment, it is proposed that, in thesecond pairs of tracks, along the extension of the centre line M22 ₂ ofthe outer ball tracks, towards the aperture end, the second arch isadjoined by a straight line which approaches the longitudinal axis L12and that, along the extension of the centre line M23 ₂ of the inner balltracks, towards the attaching end, the second arch is adjoined by astraight line which approaches the longitudinal axis L13. According to afurther characteristic it is proposed that, in the second pairs oftracks, the centre lines M22, M23 of the ball tracks in the joint centreplane EM intersect one another at an angle of 4 to 32°, wherein thetangents T22, T23 at the centre lines M22, M23 of the ball tracks of allpairs of tracks when the joint is in the aligned condition formidentical opening angles α.

Preferably, first pairs of tracks and second pairs of tracks arearranged so as to alternate around the circumference. The radial planesR1 of the first pairs of tracks and the radial planes R2 of the secondpairs of tracks, in the circumferential direction, can, moreparticularly, comprise identical pitch angles. In a special embodimentit is proposed that the first pairs of tracks and the second pairs oftracks do not extend symmetrically relative to the joint centre planeEM. More particularly, the first pairs of tracks—analogously to thepairs of tracks of UF joints—can be designed to be undercut-free whenviewed from the joint aperture end.

According to a further preferred embodiment, it is proposed that thepitch circle radius PCR₁ of the balls of the first pairs of tracks issmaller than the pitch circle radius PCR₂ of the balls of the secondpairs of tracks.

A second solution consists in providing a constant velocity joint in theform of a fixed joint with the following characteristics:

an outer joint part which comprises a longitudinal axis L12 and anattaching end and an aperture end arranged so as to be axially oppositeone another, and which is provided with outer ball tracks,

an inner joint part which comprises a longitudinal axis L13 andattaching means for a shaft pointing towards the aperture end of theouter joint part, and which is provided with inner ball tracks,

the outer ball tracks and the inner ball tracks form pairs of trackswith one another,

the pairs of track each accommodate a torque transmitting ball,

an annular ball cage is positioned between the outer joint part and theinner joint part and comprises circumferentially distributed cagewindows which each accommodate at least one of the torque transmittingballs,

the centres of the balls are held by the cage in a joint centre plane EMand, upon articulation of the joint, are guided onto the angle-bisectingplane between the longitudinal axes L12, L13,

the centre lines M22, M23 of the ball tracks of pairs of tracks arepositioned in pairs of track planes BE, BE* which extend parallelrelative to one another and symmetrically relative to radial planes R1,R2 through the longitudinal axes L12, L13,

for a first part of the pairs of tracks, the opening angle α₁ betweenthe tangents T22 ₁′, T23 ₁′ at track base lines extending parallel tothe tangents T22 ₁, T23 ₁ at the centre lines M22 ₁, M23 ₁ of the balltracks in the joint centre plane EM when the joint is in the alignedcondition with coinciding longitudinal axes L12, L13 opens from theattaching end to the aperture end,

for a second part of the pairs of tracks, the opening angle α₂ betweenthe tangents T22 ₂′, T23 ₂′ at track base lines extending parallel tothe tangents T22 ₂, T23 ₂ at the centre lines M22 ₂, M23 ₂ of the balltracks in the joint centre plane EM when the joint is in the alignedcondition with coinciding longitudinal axes L12, L13 opens from theaperture end to the attaching end, and the following applies to thecentre lines of the second pairs of tracks;

in the outer joint part, the centre line M22 ₂ of the ball tracks in theregion from the joint centre plane EM to the attaching end radiallyinwardly leaves a reference radius RB whose radius centre MBE ispositioned in the point of intersection of a perpendicular line on thetangent T22 ₂ at the centre line M22 ₂ of the ball track in the jointcentre plane EM and of a parallel axis PE, PE* relative to thelongitudinal axis L12 through a track plane BE, BE*,

in the inner joint part, the centre line M23 ₂ of the ball tracks in theregion from the joint centre plane EM to the aperture end radiallyinwardly leaves a reference radius RB′ whose radius centre MBE′ ispositioned in the point of intersection of a perpendicular line on thetangent T23 ₂′ at the centre line M23 ₂ of the ball track in the jointcentre plane EM and of a parallel axis PE, PE* relative to thelongitudinal axis L13 through a track plane BE, BE*,

in the outer joint part, the centre line M22 ₂ of the ball tracks in theregion from the joint centre plane EM to the aperture end moves radiallyoutwardly beyond said reference radius RB, and

in the inner joint part, the centre line M23 ₂ of the ball tracks 23 ₂in the region from the joint centre plane EM to the attaching end movesradially outwardly beyond said reference radius RB′.

The solution proposed here differs from the solution proposed firstwherein the centre lines of the pairs of tracks are positioned in radialplanes through the centre axes of the joint in that, in the presentcase, the centre lines of pairs of tracks of two adjoining balls extendin two parallel track planes BE, BE* which extend parallel to andsymmetrically to a radial plane R. As in the case of the first solution,the radial plane R is defined by the longitudinal axes L12, L13 when thejoint is in the aligned condition. With the track shape, in principle,being the same as in the first solution, the track shapes of the secondsolution, however, refer to parallel axes PE, PE* which are positionedin a reference plane EX through the longitudinal axes L12, L13, whichreference plane EX is positioned perpendicularly on the radial plane R.The track shapes of the second solution also refer to reference centresME which are positioned on said parallel axes PE, PE* and in the pointof intersection of the parallel axes with the joint centre plane EM.

A third solution consists in providing a constant velocity universaljoint in the form of a fixed joint with the following characteristics:

an outer joint part which comprises a longitudinal axis L12 and anattaching end and an aperture end arranged so as to be axially oppositeone another, and which is provided with outer ball tracks,

an inner joint part which comprises a longitudinal axis L13 andattaching means for a shaft pointing towards the aperture end of theouter joint part, and which is provided with inner ball tracks,

the outer ball tracks and the inner ball tracks form pairs of trackswith one another,

the pairs of tracks each accommodate a torque transmitting ball,

an annular ball cage is positioned between the outer joint part and theinner joint part and comprises circumferentially distributed cagewindows which each accommodate at least one of the torque transmittingballs,

the centres of the balls are held by the cage in a joint centre planeand, upon articulation of the joint, are guided onto the angle-bisectingplane between the longitudinal axes L12, L13,

the centre lines M22 ₁, M22 ₂ of adjoining ball tracks in the outerjoint part are positioned in pairs of first track planes BE, BE* whichextend parallel relative to one another and symmetrically relative toradial rays RS1, RS2 through the joint centre M,

the centre lines M23 ₁, M23 ₂ of adjoining ball tracks in the innerjoint part are positioned in pairs of second track planes BE′, BE*′which extend parallel relative to one another and symmetrically relativeto radial rays RS1, RS2 through the joint centre M,

the first track planes BE,BE* and the second track planes BE′, BE*′,together with radial planes R1, R2 through the longitudinal axes L12,L13, form identically sized angles γ, γa′ which extend in oppositedirections,

for a first part of the pairs of tracks, the opening angle α₁ betweenthe tangents T22 ₁′, T23 ₁′ at track base lines extending parallel tothe tangents T22 ₁, T23 ₁ at the centre lines M22 ₁, M23 ₁ of the balltracks in the joint centre plane EM when the joint is in the alignedcondition with coinciding longitudinal axes L12, L13, opens from theattaching end to the aperture end,

for a second part of the pairs of tracks, the opening angle α₂ betweenthe tangents T22 ₂′, T23 ₂′ at track base lines extending parallel tothe tangents T22 ₂, T23 ₂ at the centre lines M22 ₂, M23 ₂ of the balltracks in the joint centre plane EM when the joint is in the alignedcondition with coinciding longitudinal axes L12, L13, opens from theaperture end to the attaching end, and the following applies to thecentre lines of the second pairs of tracks:

in the outer joint part, the centre line M22 ₂ of the ball tracks in theregion from the joint centre plane EM to the attaching end radiallyinwardly leaves a reference radius RB whose radius centre MBE ispositioned in the point of intersection of a perpendicular line on thetangent T22 ₂ at the centre line M22 ₂ of the ball track in the jointcentre plane EM and of a reference axis PE, PE* through a track planeBE, BE*, in the inner joint part, the centre line M23 ₂ of the balltracks in the region from the joint centre plane EM to the aperture endradially inwardly leaves a reference radius RB′ whose radius centre MBE′is positioned in the point of intersection of a perpendicular line onthe tangent T23 ₂ at the centre line M23 ₂ of the ball tracks in thejoint centre plane EM and of a reference axis PE′, PE*′ through a trackplane BE′, BE*′,

in the outer joint part , the centre line M22 ₂ of the ball tracks inthe region from the joint centre plane EM to the aperture end movesradially outwardly beyond said reference radius RB, and

in the inner joint part, the centre line M23 ₂ of the ball tracks in theregion from the joint centre plane EM to the attaching end movesradially outwardly beyond said reference radius RB′.

According to the third solution proposed here, the centre lines of pairsof tracks of two adjoining balls in the outer joint part extend in twoparallel planes BE, BE* which extend symmetrically to and parallel to areference plane EB through the joint centre, which reference plane EB,together with a radial plane, forms an angle γ positioned in a secondreference plane EX arranged perpendicularly on the radial plane, and inthe inner part they extend in two parallel reference BE′, BE*′ whichextend symmetrically to and parallel to a reference plane EB′ throughthe joint centre, which reference plane EB′, together with a radialplane, forms an angle γ′ positioned in a second reference plane EXarranged perpendicularly on the radial plane. Said radial plane R, as inthe case of the second solution, is defined by the longitudinal axesL12, L13 when the joint is in the aligned condition. With, in principle,the same track shape as in the second alternative, the track shapesaccording to the third solution, however, refer to parallel axes in theinner joint part and outer joint part, which axes are arranged so as toextend, in parallel, relative to one another in pairs, which intersectone another in pairs and which are positioned in a second referenceplane EX through the longitudinal axes L12, L13 which is arrangedperpendicularly on the radial plane R; they also refer to referencecentres which are positioned on said parallel axes and in the point ofintersection of the parallel axes with the joint centre plane EM.

Joints according to the above-described second and third solutionscomprise a number of track pairs which can be divided by two if only onetrack is positioned in each track plane BE, BE*, BE′ BE*′. They comprisea number of track pairs which can be divided by four if each of thetrack planes BE, BE*, BE′, BE*′ contains two symmetrically shaped pairsof tracks arranged substantially opposite one another.

As explained above, the further embodiments of joints according to thesecond and third solutions—while the respective reference places arechanged—substantially correspond to joint embodiments according to thefirst solution. This results in the following:

A first advantageous embodiment comprises the following furthercharacteristics of the second pairs of tracks: in the outer joint part,the local radius R1 of the centre line M22 ₂ in the joint centre planeEM is smaller than the reference radius RB,

in the inner joint part, the local radius R1′ of the centre line M23 ₂in the joint centre plane EM is smaller than the reference radius RB′.

A first advantageous embodiment comprises the following furthercharacteristics of the second pairs of tracks:

in the outer joint part, the centre line M22 ₂ of the ball tracksextends from the joint centre plane EM to the attaching side radiallyoutside a reference radius RZ whose radius centre is positioned in thejoint centre plane EM on one of the reference axes PE, PE*, and

in the inner joint part , the centre line M23 ₂ of the ball tracksextends from the joint centre plane EM to the aperture end radiallyoutside a reference radius RZ′whose radius centre is positioned in thejoint centre plane EM on one of the reference axes PE, PE*, PE′, PE*′.

A further advantageous embodiment is characterised by the followingfurther characteristics:

in the outer joint part, the centre line M22 ₂ of the ball tracksextends from the joint centre plane EM to the aperture end radiallyoutside the reference radius RB and

in the inner joint part, the centre line M23 ₂ of the ball tracksextends from the joint centre plane EM to the attaching end radiallyoutside the reference radius RB′.

Furthermore, the following further characteristics are proposed for thesecond pairs of tracks:

in the outer joint part, the centre line M22 ₂ of the ball tracksextends from the joint centre plane EM to the aperture end radiallyinside a reference radius RZ whose radius centre is positioned in thejoint centre plane EM on one of the parallel axes PE, PE*,

in the inner joint part, the centre line M23 ₂ of the ball tracksextends from the joint centre plane EM to the attaching end radiallyinside a reference radius RZ′ whose radius centre is positioned in thejoint centre plane EM on one of the parallel axes PE, PE*, PE′, PE*40 .

A further proposal concerns the following characteristics of the secondpairs of tracks:

the centre lines M22 ₂, M23 ₂ of the outer ball tracks and inner balltracks each comprise at least two arched portions which are curved inopposite senses and which adjoin one another in a turning point,

the turning points W22 ₂ of the outer ball tracks are positioned in atrack plane BE, BE* at a distance from the centre plane EM towards theaperture end,

the turning points W23 ₂ of the inner ball tracks are positioned in atrack plane BE, BE*, BE′, BE*′ at a distance from the centre plane EMtowards the aperture end,

the turning points W22 ₂, W23 ₂ are each positioned below a maximum ofthe distance between the centre lines M22 ₂, M23 ₂ and the parallel axesPE, PE*, PE′, PE*′.

A further embodiment comprises the following characteristics of thesecond pairs of tracks:

the track centre lines M22 ₂ of the outer ball tracks comprise a firstarch with the radius R1 whose centre Ml in a track plane BE, BE* isoffset by a first axial offset O1 a from the centre plane EM of thejoint towards the attaching end and by a first radial offset O1 routwardly from a parallel axis PE, PE* and, in the region adjoining saidarch, towards attaching end, they comprise a second arch with the radiusR2 whose centre M2 in the track plane BE, BE* is offset by a secondaxial offset O2 a from the centre plane EM of the joint towards theaperture end and is outwardly offset from the parallel axis PE, PE′ by asecond radial offset O2 r which is greater than the sum of the firstradius R1 and the first radial offset O1 r,

the track centre lines M23 ₂ of the outer ball tracks comprise a firstarch with the radius R1′ whose centre M1′ in a track plane BE, BE*, BE′,BE*′ is offset by a first axial offset O1 a′ from the centre plane EM ofthe joint towards the aperture end and is offset outwardly by a firstradial offset from a parallel axis PE, PE*, PE′, PE*′ and, in the regionadjoining said arch, towards the aperture end, they comprise a secondarch with the radius R2′ whose centre M2′ in the track plane BE, BE*,BE′, BE*′ is offset by a second axial offset O2 a′ from the centre planeEM of the joint towards the attaching end and is outwardly offset fromthe parallel axis PE, PE*, PE′, PE*′ by a second radial offset O2 r′which is greater than the sum of the first radius R1′ and the firstradial off-set O1 r′.

A further proposal comprises the following characteristics of the secondpairs of tracks:

the radius of curvature of the centre lines M22 of the outer ball tracksdecreases in the extension from the centre plane EM towards theattaching end and the radius of curvature of the centre plane M23 of theinner ball tracks decreases in the extension from the centre plane EM tothe aperture end.

A further proposal comprises the following characteristics of the secondpairs of tracks:

the track centre lines of the outer ball tracks 22 ₂ comprise a thirdarch with the radius R3 which, tangentially, while having the same senseof curvature, adjoins the first arch with the radius R1 and whose radiusR3 is smaller than the radius R1,

the track centre lines M23 ₂ of the inner ball tracks comprise a thirdarch with the radius R3′ which, tangentially, while having the samesense of curvature, adjoins the first arch with the radius R1′ and whoseradius R3′ is smaller than the radius R1′

Furthermore, it is proposed that, in the second pairs of tracks, alongthe extension of the centre line M22 of the outer ball tracks, towardsthe aperture end, the second arch is adjoined by an axis-parallelstraight line G3 and that, along the extension of the centre line M23 ofthe inner ball tracks, the second arch, towards the attaching end, isadjoined by an axis-parallel straight line G3′.

According to an alternative embodiment, it is proposed that, in thesecond pairs of tracks along the extension of the centre line M22 ₂ ofthe outer ball tracks, towards the aperture end, the second arch isadjoined by a straight line which approaches the parallel axis PE, PE′and that along the extension of the centre line M23 ₂ of the inner balltracks, the second arch, towards the attaching end, is adjoined by astraight line which approaches the parallel axis PE, PE*, PE′, PE*′.

In this case, too, it is proposed that, in the second pairs of tracks,the centre lines M22, M23 of the ball tracks in the joint centre planeEM intersect one another at an angle of 4 to 32°, wherein the tangentsT22, T23 at the centre lines M22, M23 of the ball tracks 22, 23 of allpairs of tracks form identical opening angles α when the joint is in thealigned condition.

A joint of the shape described here preferably comprises a number ofpairs of balls which can be divided by four. More particularly, it isproposed that the balls of two adjoining pairs of tracks positioned inparallel track planes BE, BE′ are received in a common cage window ofthe ball cage.

As already explained above, the track planes BE, BE*, according to thesecond solution, can extend parallel to the longitudinal axes L12, L13and the track planes BE, BE*, BE′ BE*′, according to the third solution,can extend at a helix angle γ, γ′ relative to the longitudinal axes L12,L13.

According to a preferred embodiment, the pitch angle 2φ between thepairs of tracks whose balls are received in a common cage window issmaller than the pitch angle between adjoining pairs of tracks whoseballs are received in different windows. Between the helix angle γ andthe pitch angle 2φ there can exist the relation γ=α/2·tan φ, with α/2being the track inclination angle and half the opening anglerespectively.

Furthermore, it is proposed that of two directly adjoining pairs oftracks one constitutes a first pair of tracks and one a second pair oftracks. In addition, it is proposed that of two pairs of trackspositioned in one track plane, one constitutes a first pair of tracksand one a second pair of tracks, i.e. two substantially radially opposedtracks open towards the aperture end on the one hand and towards theattaching end on the other hand.

The invention will be explained in greater detail with reference to thedrawings which show preferred embodiments of inventive joints ascompared to a joint according to the state of the art.

FIG. 1 shows an inventive joint according to the first solution

-   -   a) in a cross-section    -   b) in a longitudinal section along sectional line A-A    -   c) in a longitudinal section along sectional line B-B

FIG. 2 shows an inventive joint according to the second solution

-   -   a) in a cross-section    -   b) in a longitudinal section along sectional line A-A    -   c) in a longitudinal section along sectional line B-B

FIG. 3 shows an inventive joint according to FIG. 2 of the thirdsolution

-   -   a) in a cross-section    -   b) in a longitudinal section along sectional line A-A.

FIG. 4 shows geometric relations with reference to a pair of balls in ajoint according to FIG. 3

-   -   a) in a cross-section    -   b) in a longitudinal section through a track plane    -   c) in a longitudinal section through a pair of balls

FIG. 5 shows the longitudinal axes and the track centre lines of thesecond tracks of an inventive joint in a first embodiment

-   -   a) for the outer joint part    -   b) for the inner joint part

FIG. 6 shows the longitudinal axes and the track centre lines of thesecond tracks of an inventive joint in a second embodiment

-   -   a) for the outer joint part    -   b) for the inner joint part.

FIGS. 1 a to 1 c will be described jointly below. A joint 11 comprisesan outer joint part 12, an inner joint part 13, torque transmittingballs 14 as well as a ball cage 15. The cage comprises a spherical outerface 16 which is guided in the outer joint part and a spherical innercage face 17 which is guided on the inner joint part, with said secondcontact not being compulsory. The balls 14 are held in circumferentiallydistributed cage windows 18 in the ball cage 15 in a joint centre planeEM. The outer joint part 12 is shown to comprise a longitudinal axis L12and the inner joint part is shown to comprise a longitudinal axis L13.The point of intersection of the longitudinal axes L12, L13 with thejoint centre plane EM forms the joint centre M. The outer joint part 12comprises a base 19 which can change into an attaching journal forexample, as well as an aperture 20 into which it is possible to insert ajournal connectable to the inner joint part. For this purpose, the innerjoint part 13 comprises an insertion aperture 21. Hereafter, theposition of the base 19 indicates the axial direction “towards theattaching end” and the position of the aperture 20 indicates the axialdirection “towards the aperture end”. These terms are also used withreference to the inner joint part, with the actual attachment of a shaftto the inner joint part not being taken into account. Starting from thecentre plane EM, the ball contact angles β_(max)/2 have been entered forthe maximum articulation angle β_(max) of the inner joint part 13relative to the outer joint part 12 in both directions. First pairs oftracks 22 ₁, 23 ₁ with first balls 14 ₁ and second pairs of tracks 22 ₂,23 ₂ with second balls 14 ₂ have been arranged so as to alternate aroundthe circumference. The shape of the first pairs of tracks 22 ₁, 23 ₁ canbe taken from section A-A and the shape of the second pairs of tracks 22₂, 23 ₂ from section B-B. The first balls 14 ₁ are in contact with firstouter ball tracks 22 ₁ in the outer joint part and first inner balltracks 23 ₁ in the inner joint part. The centre lines M22 ₁, M23 ₁ ofsaid tracks are of the type as used in UF tracks and are composed of acircular arch and a tangentially adjoining straight line. In the alignedposition as illustrated, the tangents T22 ₁′, T23 ₁′ at the balls 14 ₁in the contact points with the tracks 22 ₁, 23 ₁ form an opening angleα1 which opens towards the aperture end. The second balls 14 ₂ areguided in outer ball tracks 22 ₂ in the outer joint part and inner balltracks 23 ₂, in the inner joint part. The balls 14 ₂ are shown to be incontact with the track base of the ball tracks, which contact does notnecessarily have to be provided. In the aligned position as illustrated,the tangents T22 ₂′, T23 ₂′ at the balls 14 ₂ in the contact points withthe tracks 22 ₂, 23 ₂ form an opening angle α₂ which opens towards theattaching end. For describing the ball tracks 22, 23, reference is madebelow to the centre lines M22 ₂, M23 ₂ of the ball tracks. The centreplane EM is shown to comprise tangents T22 ₂, T23 ₂ at the centre lineswhich tangents are positioned parallel to the above-mentioned tangentsT22 ₂′, T23 ₂′. The angle α₂ between said tangents T22 ₂, T23 ₂ rangesbetween 4 and 32°.

It can be seen that each pair of tracks is positioned with its centrelines M22, M23 in a radial plane R₁, R₂ through the joint, that saidradial planes R are at identical angular distances from one another andthat one ball 14 each is accommodated by a cage window 18 in the ballcage 15.

FIGS. 2 a to 2 c will be described jointly below. They show a joint 11in an embodiment which has been modified as compared to the embodimentaccording to FIG. 1. Nevertheless, identical details have been given thesame reference numbers as in FIGS. 1 a to 1 c. An inventive joint 11 insaid second embodiment comprises ball tracks 22, 23 which are positionedin track planes BE, BE* which are arranged in pairs symmetricallyrelative to radial planes R through the joint. Illustration b) shows anangled section according sectional line A-A, which angled section, onthe one hand, extends through the track plane BE and a first pair oftracks 22 ₁, 23 ₁ with a first ball 14 ₁ and, on the other hand, througha radial plane between two pairs of tracks. Illustration c) shows a bentsection according to sectional line B-B, which bent section extendsthrough a track plane BE* and a second pair of tracks with second balltracks 22 ₂, 23 ₂ on the one hand and through a radial plane between twopairs of tracks on the other hand. It is possible to see pairs of trackpairs which are distributed around the circumference and which comprisea first pair of tracks 22 ₂, 23 ₁ and a second pair of tracks 22 ₂, 23 ₂and which are held in a common cage window 18. The pitch angle of saidpairs of track pairs is smaller than that between two adjoining pairs oftracks which are not associated with a pair of track pairs. In theembodiment shows here, first pairs of tracks and second pairs of tracksalternate around the circumference.

As can be seen in illustration b), the first balls 14 ₁ are guided infirst pairs of tracks consisting of outer tracks 22 ₁ and inner tracks23 ₁ which are of the type as contained in UF joints, which means thatthe centre lines M22, M23 of said pairs of tracks are composed of radiiand adjoining tangential straight lines. The tangents T22 ₁, T23 ₁′ atthe balls in the tracks form a first opening angle α₁ which openstowards the aperture end of the outer joint part.

Illustration c) shows a second ball 14 ₂ which is held in second outerball tracks 22 ₂ and second inner ball tracks 23 ₂. Tangents T22 ₂, T23₂′ at the balls 14 ₂ form an opening angle α₂ with one another whichopens towards the attaching end of the outer joint part. As far as thetrack extension is concerned, reference will be made below to the centrelines M22 ₂, M23 ₂. In the joint centre plane EM, the tangents T22 ₂,T23 ₂ at the centre line M22 ₂, M23 ₂ intersect one another at theabove-mentioned angle α₂.

The track planes BE, BE* contain parallel axes PE, PE* extendingrelative to the longitudinal axes at the shortest distance, which thusform sectional lines between the track planes and a reference plane EX1,EX2 positioned perpendicularly relative to the respective radial planeR1, R2. On the parallel axes PE, PE*, there are positioned track centresME, ME* at the shortest distance from the joint centre M. If there arearranged four pairs of tracks symmetrically to three or four radialplanes R with identical pitch angles relative to one another, there areobtained joints with twelve or sixteen pairs of tracks 22, 23 and,accordingly, with twelve or sixteen balls 14. In accordance withillustration a) the centre ME1, ME1* shown in illustrations b) and c) isnot the joint centre, but the track curve centre in one of the trackplanes BE1, BE1*.

FIGS. 3 a and 3 b will be described jointly below. In principle,illustration a) corresponds to illustration a) of FIG. 2, but in thiscase, the sectional line A-A extends parallel to a reference plane EX1through the balls of a pair of track pairs. Illustration b) shows afirst reference plane EB for outer ball tracks, which is positionedperpendicularly on said reference plane EX1 and contains a radial ray RSthrough the joint centre M. Said reference plane EB′, together with theradial plane R extending through the longitudinal axes L12, L13, forms ahelix angle γ. Parallel to the reference plane EB, there are positionedthe reference planes BE and BE* in which there extend the centre linesof the outer ball tracks of a pair of tracks. Furthermore, illustrationb) shows a first reference plane EB′ for inner ball tracks which is alsopositioned perpendicularly on said reference plane EX and contains theradial ray RS through the joint centre M. Said reference plane EB′,together with the radial plane R through the longitudinal axes L12, L13forms a helix angle γ′ which is identical in size and extends in theopposite direction to y. The track planes BE′, BE*′ containing thecentre lines of the inner ball tracks of a pair of tracks extendparallel to the reference plane EB′. The centre lines of each pair oftracks intersect one another in the joint centre plane EM.

FIGS. 4 a and 4 c will be described jointly below. Illustration a) showsa cross-section through a ball assembly which consists of four pairs ofballs 14 ₁, 14 ₂ according to FIG. 3 and which is positioned in thejoint centre plane. The pitch angle between the balls 14 ₁, 14 ₂ of apair of balls and the radial plane R1 positioned therebetween amounts toφ_(o) and φ_(o)′ respectively. The ball tracks are arranged at adistance from a reference plane EX1, which distance corresponds to thepitch circle radius PCR multiplied by the cosine of φ_(o). Theperpendicular distance of the balls of a pair of balls from said radialplane R1 has been given the symbol a. The track planes BE₁, BE₁* asshown represent the passage of the track planes BE, BE* of the outerball tracks and the passage of the track planes BE′, BE*′ of the innerball tracks through the joint centre plane.

In illustration b), in the section through one of the track planes BE₁,BE₁*, the track opening angle between the tangents T22, T23 at the trackcentre lines of a second pair of tracks has been given as α₂, with thedrawn-in angle legs representing the tangents T22′, T23′ at the trackbase lines of the track. α2/2 thus corresponds to half the opening angleand track inclination angle respectively.

Illustration c) shows a pair of balls 14 ₁, 14 ₂ with the outer trackplanes EB, EB* and the inner track planes EB′, EB*′. The penetrationpoints D1, D2 as shown in illustration b) are also given.

The following equations apply to the ideal case wherein said tracktangents T22, T23 penetrate the radial planes R in the axes L12, L13,i.e. the penetration points D1 and D2 are positione on the longitudinalaxes L12, L13.

The following relations apply: $\begin{matrix}{\alpha = {{{PCR} \cdot \sin}\quad\varphi_{0}^{1}}} & (1) \\{{\frac{{{PCR} \cdot \cos}\quad\varphi_{0}^{1}}{x} = {\tan\frac{\alpha 2}{2}}}{with}{x = \frac{{PCR}\quad\cos\quad\varphi_{0}^{1}}{\tan\frac{\alpha 2}{2}}}} & (2) \\{{\frac{a}{x} = {\sin\quad\mu}}{{{i.e.\sin}\quad\mu} = {{\frac{{{PCR} \cdot \sin}\quad\varphi_{0}^{1}}{{{PCR} \cdot \cos}\quad\varphi_{0}^{1}} \cdot \tan}\frac{\alpha 2}{2}}}} & (3)\end{matrix}$for small angles $\frac{\alpha 2}{2}$and γ the following approximation applies: sin  ≈ arc tan  ≈ arc${{arc}\quad\mu} \approx {\tan\quad{\varphi_{0}^{1} \cdot {arc}}\frac{\alpha 2}{2}{uldsomiL}}$$\mu \approx {{\frac{\alpha 2}{2} \cdot \tan}\quad\varphi_{0}^{1}}$

FIG. 5 a shows the track centre line M22 of an outer ball track 22according to any one of FIGS. 1 to 3, which track centre line M22extends parallel to a track base line. The centre line M22 of a track inthe outer part is composed of a first radius R1 around a centre M1 withthe first axial offset O1 a and a radial offset O1 r as well as of asecond radius R2 with a second axial offset O2 a and a second radialoffset O2 r. The transition is indicated by a turning point W22. Thesecond radius R2 is tangentially adjoined by a straight line G3extending parallel to the axis L12, PE, PE*. The centre plane EM isshown to comprise the tangent T22 and the centre line M22 whichintersects a longitudinal axis L12, PE, PE* at an angle α/2. Aperpendicular line on the tangent T22 intersects the longitudinal axisL12, PE; PE* in the reference centre MB, MBE of a reference radius RB. Afurther reference radius RZ is entered around the track centre M, ME. Tothe left of the centre plane EM, towards the attaching end 19, thecentre line M22 extends inside the radius RB and outside the radius RZ.To the right of the centre plane EM, towards the aperture end 20, thecentre line M22 extends substantially outside the radius RB. The radialball movement of a ball on its path along the ball track with referenceto the track centre M, ME has been given the reference symbol e. Thiscorresponds to the minimum thickness of the ball cage in the region ofthe cage window, with a safety allowance being required to avoid edgebearing.

FIG. 5 b shows the track centre lines M23 of the associated inner balltracks 23 according to any one of FIGS. 1 to 3, which track centre linesM23 extend parallel relative to the track base lines. The centre lineM23 of a track 23 in the inner part 13 is composed of a first radius R1′around a centre M1′ and of a second radius R2′ around a centre M2′. Thetransition is indicated by a turning point W23. The second radius R2′ isadjoined by a straight line G32′ which extends parallel relative to theaxis L13, PE, PE*, PE′, PE*′. The centre M1′ comprises an axial offsetO1 a′ and a radial offset O1 r′ and the centre M2′ comprises an axialoffset O2 a′ and a radial offset O2 r′. In the centre plane EM, there isshown the tangent T23 at the centre line M23, which intersects alongitudinal axis L13, PE, PE*, PE′, PE*′ at the angle α/2. Aperpendicular line at the tangent T23 intersects the longitudinal axisL13, PE; PE*, PE′, PE*′ in the reference centre MB′, MBE′ of a referenceradius RB′. A further reference radius RZ′ has been entered around thetrack centre M, ME. To the right of the centre plane EM, towards theaperture end 20, the centre line M23 extends inside the radius RB′ andoutside the radius RZ′. To the left of the centre plane EM, towards theattaching end 19, the centre line M23 extends at least predominatelyoutside the radius RB′. The radial ball movement of a ball on its pathalong the ball track with reference to the track centre M, ME has beengiven the reference symbol e. The two centre lines M22, M23 of FIGS. 5a, 5 b intersect one another in the joint centre plane EM at the angle αand extend mirror-symmetrically relative to said centre plane.

FIG. 6 a, in a modified embodiment, shows the track centre line M22 ofan outer ball track 22, which track centre line M22 extends parallel toa track base line. The centre line M22 of a track in the outer jointpart is composed of a first radius R1 around a centre M1 with a firstaxial offset O1 a and a radial offset O1 r as well as of a second radiusR2 with a second axial offset O2 a and a second radial offset O2 r aswell as of a third radius R3 which adjoins the radius R1 opposite to theradius R2, which is smaller than the radius R1 and is curved in the samedirection, with the position of its centre M3 not being given detaileddimensions. The transition between the first and second radius isindicated by the turning point W22. The second radius R2 is tangentiallyadjoined by a straight line G3 which extends parallel to the axis L12,PE, PE*. In the centre plane EM, there are shown the tangent T22 and thecentre line M22 which intersects a longitudinal axis L12, PE, PE* at theangle α/2. A perpendicular line on the tangent T22 intersects thelongitudinal axis L12, PE; PE* in the reference centre MB, MBE of areference radius RB. A further reference radius has been entered aroundthe track centre M, ME. To the left of the centre plane, towards theattaching end 19, the centre line M22 extends inside the radius RB andoutside the radius RZ. To the right of the centre plane EM, towards theaperture end 20, the centre line M22 extends predominately outside theradius RB. The radial ball movement of a ball on its path along the balltrack with reference to the track centre M, ME has been given thereference symbol e. This corresponds to the minimum thickness of theball cage in the region of the cage windows, with a safety allowancehaving to be provided to avoid edge bearing.

FIG. 6 b, in a modified embodiment, shows the track centre line M23 ofan inner ball track 23, which track centre line M23 extends parallel toa track base line. The centre line M23 of a track 23 in the inner jointpart 13 is composed of a first radius R1 around a centre M1′, of asecond radius R2′ around a centre M2′ as well as of a third radius R3′which adjoins the radius R1′ opposite to the radius R2′, which issmaller than said radius R1 and is curved in the same direction. Thesecond radius R2′ is adjoined by a straight line G3 which extendsparallel to the axis L13, PE, PE*, PE′, PE*′. The centre M2′ comprisesan axial offset O1 a′ and a radial offset O1 r′ and the centre M2′comprises an axial offset O2 a′ and a radial offset O2 r′. The positionof the centre M3′ has not been given detailed dimensions. In the centreplane EM, there are shown the tangent T23 and the centre line M23 whichintersects a longitudinal axis L13, PE, PE*, PE′, PE*′ at the angle α/2.A perpendicular line on the tangent T23 intersects the longitudinal axisL12, PE; PE*, PE′, PE*′ in the reference centre MB′, MBE′ of a referenceradius RB′ . A further reference radius RZ′ has been entered around thetrack centre M, ME. To the right of the centre plane EM, towards theaperture end 20, the centre line M23 extends inside the radius RB′ andoutside the radius RZ′. To the left of the centre plane EM, towards theattaching end 19, the centre line M23 extends predominately outside theradius RB′. The radial ball movement of a ball on its path along theball track with reference to the track centre M, ME has been given thereference symbol e. The two centre lines M22, M23 of FIGS. 6 a, 6 bintersect one another in the joint centre plane EM at the angle α andextend mirror-symmetrically relative to said centre plane.

Counter Track Joint for Large Articulation Angles LIST OF REFERENCENUMBERS

11 joint

12 outer joint part

13 inner joint part

14 ball

15 cage

16 outer cage face

17 inner cage face

18 cage window

19 base

20 aperture

21 insertion aperture

22 outer ball track

23 inner ball track

24 track base of outer ball track

25 track base of inner ball track

26 track flank

27 track flank

EM joint centre plane

L12 longitudinal axis of outer part

L13 longitudinal axis of inner part

M22 centre line of track 22

M23 centre line of track 23

1. A constant velocity joint comprising: an outer joint part whichcomprises a first longitudinal axis and an attaching end and an apertureend arranged so as to be axially opposite one another, and outer balltracks; an inner joint part which comprises a second longitudinal axisand an attachment for a shaft pointing towards the aperture end of theouter joint part, and inner ball tracks, the outer ball tracks and theinner ball tracks form pairs of tracks with one another which, eachaccommodate a torque transmitting ball; and an annular ball cage betweenthe outer joint part and the inner joint part and comprisingcircumferentially distributed cage windows which each accommodate atleast one of the torque transmitting balls, the centers of the balls areheld by the cage in a joint center plane and, upon articulation of thejoint, are guided onto the angle-bisecting plane between the first andsecond longitudinal axes, wherein center lines of the outer and innerball tracks of pairs of tracks are positioned in radial planes throughthe joint, and for first pairs of tracks, a first opening angle (α₁)between tangents at track base lines extending parallel to tangents atthe center lines of the ball tracks in the joint center plane when thejoint is in the aligned condition with coinciding longitudinal axes,opens from the attaching end to the aperture end, for second pairs oftracks, a second opening angle (α₂) between tangents at track base linesextending parallel to tangents at the center lines of the ball tracks inthe joint center plane when the joint is in the aligned condition withcoinciding longitudinal axes, opens from the aperture end to theattaching end, and for the second pairs of tracks: in the outer jointpart, the center line of the ball tracks in a region from the jointcenter plane to the attaching end radially inwardly departs a firstreference radius centered in a point of intersection of a perpendicularline on a tangent at the center line of the ball track in the jointcenter plane and the first longitudinal axis, in the inner joint part,the center line of the ball tracks in a region from the joint centerplane to the aperture end radially inwardly departs a second referenceradius centered in a point of intersection of a perpendicular line on atangent at the center line of the ball track in the joint center planeand the second longitudinal axis, in the outer joint part, the centerline of the ball tracks in the region from the joint center plane to theaperture end moves radially outwardly beyond said first referenceradius, and in the inner joint part, the center line of the ball tracksin the region from the joint center plane to the attaching end movesradially outwardly beyond said second reference radius. 2-47. (canceled)48. A constant velocity joint according to claim 1 wherein, for thesecond pairs of tracks: in the outer joint part, a first local radius ofcurvature (R1) of the center line in the joint center plane is smallerthan the first reference radius, and in the inner joint part, a secondlocal radius of curvature (R1′) of the center line in the joint centerplane is smaller than the second reference radius.
 49. A constantvelocity joint according to claim 1 wherein, for the second pairs oftracks: in the outer joint part, the center line of the ball tracksextends from the joint center plane to the attaching end radiallyoutside a third reference radius (RZ) whose radius center is positionedin the joint center (M), and in the inner joint part, the center line ofthe ball tracks extends from the joint center plane to the aperture endradially outside a fourth reference radius (RZ′) whose radius center ispositioned in the joint center.
 50. A joint according to claim 1wherein, for the second pairs of tracks: in the outer joint part, thecenter line of the ball tracks extends from the joint center plane tothe aperture end radially outside the first reference radius (RB) and,in the inner joint part, the center line of the ball tracks extends fromthe joint center plane to the aperture end radially outside a thirdreference radius (RZ′).
 51. A joint according to claim 1 wherein, forthe second pairs of tracks: in the outer joint part, the center line ofthe ball tracks extends from the just center plane to the aperture endradially inside a third reference radius (RZ) around the joint centerand, in the inner joint part, the center line of the ball tracks extendsfrom the joint center plane to the attaching end radially inside afourth reference radius (RZ′) around the joint center.
 52. A constantvelocity joint according to claim 1 wherein, for the second pairs oftracks: the center lines of the outer ball tracks and inner ball trackseach comprise at least two arched portions which are curved in oppositesenses and which adjoin one another in a turning point, the turningpoints of the outer ball tracks being positioned at a distance from thecenter plane towards the aperture end, the turning points of the innerball tracks are positioned at a distance from the center plane towardsthe attaching end, and wherein the turning points are each positionedbelow a maximum of a distance of the center lines from the longitudinalaxes.
 53. A constant velocity joint according to claim 1 wherein, forthe second pairs of tracks: the track center lines of the outer balltracks comprise a first arch with a radius (R1) whose center is offsetby a first axial offset (O1 a) from the center plane of the jointtowards the attaching end and by a first radial offset (O1 r) from thefirst longitudinal axis towards the ball track and, in the regionadjoining said arch, towards the attaching end, they comprise a secondarch with a radius (R2) whose center is offset outwardly by a secondaxial offset (O2 a) from the center plane of the joint towards theaperture end and by a second radial offset (O2 r) which is greater thana sum of the first arch radius (R1) and the first radial offset (O1 r)from the first longitudinal axis, and the track center lines of theinner ball tracks comprise a first arch with a radius (R1′) whose centeris offset by a first axial offset (O1 a′) from the center plane of thejoint towards the aperture end and by a first radial offset (O1 r′) fromthe second longitudinal axis to the ball track and, in the regionadjoining said arch, towards the aperture end, they comprise a secondarch with a radius (R2′) whose center is offset outwardly by a secondaxial offset (O2 a′) from the center plane of the joint towards theattaching end and by a second radial offset (O2 r′) which is greaterthan a sum of the first arch radius (R1′) and the first radial offset(O1 r′) from the second longitudinal axis.
 54. A constant velocity jointaccording to claim 1 wherein, for the second pairs of tracks: the radiusof curvature of the center lines of the outer ball tracks decreases inits extension from the center plane to the attaching end, and the radiusof curvature of the center line of the inner ball tracks decreases inits extension from the center plane to the aperture end.
 55. A constantvelocity joint according to claim 53 wherein, for the second pairs oftracks: the radius of curvature of the center lines of the outer balltracks decreases in its extension from the center plane to the attachingend, and the radius of curvature of the center line of the inner balltracks decreases in its extension from the center plane to the apertureend.
 56. A constant velocity joint according to claim 55 wherein, forthe second pairs of tracks: the track center lines of the outer balltracks comprise a third arch with a radius (R3) which tangentially,while having the same sense of curvature, adjoins the first arch andwhose radius of curvature (R3) is smaller than the first arch radius(R1), and the track center lines of the inner ball tracks comprise athird arch with a radius (R3′) which tangentially, while having the samesense of curvature, adjoins the first arch and whose radius of curvature(R3′) is smaller than the first arch radius of curvature (R1′).
 57. Ajoint according to claim 53 wherein, in the second pairs of tracks,along the extension of the center line of the outer ball tracks, towardsthe aperture end, the second arch is adjoined by an axis-parallelstraight line (G3) and wherein, along the extension of the center lineof the inner ball tracks, towards the attaching end, the second arch(R2′) is adjoined by an axis-parallel straight line (G3′).
 58. A jointaccording to claim 53 wherein, in the second pairs of tracks, along theextension of the center line of the outer ball tracks, towards theaperture end, the second arch is adjoined by a straight line whichapproaches the first longitudinal axis and wherein, along the extensionof the center line of the inner ball tracks, towards the attaching end,the second arch (R2′) is adjoined by a straight line which approachesthe second longitudinal axis.
 59. A joint according to claim 1 wherein,in the second pairs of tracks, the center lines of the ball tracks inthe joint center plane intersect one another at an angle of 4 to 32°,and wherein tangents at the center lines of the ball tracks of all pairsof tracks form identical opening angles (α) when the joint is aligned.60. A joint according to claim 1 wherein the first pairs of tracks andthe second pairs of tracks are arranged so as to alternate around thecircumference.
 61. A joint according to claim 1 wherein radial planes ofthe first pairs of tracks and the radial planes of the second pairs oftracks comprise identical pitch angles in the circumferential direction.62. A joint according to claim 1 wherein the first pairs of tracks andthe second pairs of tracks do not extend symmetrically relative to thejoint center plane.
 63. A joint according to claim 1 wherein a pitchcircle radius of the balls of the first pairs of tracks and a pitchcircle radius of the balls of the second pairs of tracks differ in size,with their size ratio ranging from 0.8 to 1.0.
 64. A constant velocityfixed joint comprising: an outer joint part which comprises a firstlongitudinal axis and an attaching end and an aperture end arranged soas to be axially opposite one another, and outer ball tracks; an innerjoint part which comprises a second longitudinal axis and an attachmentfor a shaft pointing towards the aperture end of the outer joint part,and inner ball tracks, the outer ball tracks and the inner ball tracksform pairs of tracks with one another which each accommodate a torquetransmitting ball; an annular ball cage between the outer joint part andthe inner joint part and comprising circumferentially distributed cagewindows which each accommodate at least one of the torque transmittingballs, the centers of the balls are held by the cage in a joint centerplane and, upon articulation of the joint, are guided onto theangle-bisecting plane between the first and second longitudinal axes,wherein center lines of the outer and inner ball tracks, of pairs oftracks are positioned in pairs of track planes which extendsubstantially parallel relative to one another and symmetricallyrelative to radial planes through the first and second longitudinalaxes, for first pairs of tracks, a first opening angle (α₁) betweentangents at track base lines extending parallel to tangents at thecenter lines of the ball tracks in the joint center plane when the jointis aligned with coinciding longitudinal axes opens from the attachingend to the aperture end, for second pairs of tracks, second openingangle (α₂) between tangents at track base lines extending parallel totangents at the center lines of the ball tracks in the joint centerplane when the joint is aligned with coinciding longitudinal axes opensfrom the aperture end to the attaching end, and for the center lines ofthe second pairs of tracks: in the outer joint part, the center line ofthe ball tracks in a region from the joint center plane to the attachingend radially inwardly departs a first reference radius centered in apoint of intersection of a perpendicular line on a tangent at the centerline of the ball track in the joint center plane and of a parallel axisrelative to the first longitudinal axis through a track plane; In theinner joint part, the center line of the ball tracks in a region fromthe joint center plane to the aperture end radially inwardly departs asecond reference radius centered in a point of intersection of aperpendicular line on a tangent at the center line of the ball track inthe joint center plane and of a parallel axis relative to the secondlongitudinal axis through a track plane; in the outer joint part, thecenter line of the ball tracks in the region from the joint center planeto the aperture end moves radially outwardly beyond said first referenceradius; and in the inner joint part, the center line of the ball tracksin the region from the joint center plane to the attaching end movesradially outwardly beyond said second reference radius.
 65. A constantvelocity joint according to claim 64 wherein for the second pairs oftracks: in the outer joint part, a first local radius (R1) of curvatureof the center line in the joint center plane is smaller than the firstreference radius, and in the inner joint part, a second local radius(R1′) of curvature of the center line in the joint center plane issmaller than the second reference radius.
 66. A constant velocity jointaccording to claim 64 wherein for the second pairs of tracks: in theouter joint part, the center line of the ball tracks extends from thejoint center plane to the attaching end radially outside a thirdreference radius (RZ) whose radius center is positioned in the jointcenter plane (EM) on one of the parallel axes, and in the inner jointpart, the center line of the ball tracks extends from the joint centerplane to the aperture end radially outside a fourth reference radius(RZ′) whose radius center is positioned in the joint center plane on oneof the parallel axes.
 67. A joint according to claim 64 wherein for thesecond pairs of tracks: in the outer joint part, the center line of theball tracks extends from the joint center plane to the aperture endradially outside the first reference radius, and in the inner jointpart, the center line of the ball tracks extends from the joint centerplane to the attaching end radially outside the second reference radius.68. A constant velocity joint according to claim 64 wherein for thesecond pairs of tracks: in the outer joint part, the center line of theball tracks extends from the joint center plane to the aperture endradially inside a third reference radius (RZ) whose radius center (ME)is positioned in the joint center plane (EM) on one of the parallelaxes, and in the inner joint part, the center line of the ball tracksextends from the joint center plane to the attaching end radially insidea fourth reference radius (RZ′) whose radius center Is positioned in thejoint center plane on one of the parallel axes.
 69. A constant velocityjoint according to claim 64 wherein for the second pairs of tracks. thecenter lines of the outer ball tracks and inner ball tracks eachcomprise at least two arched portions which are curved in oppositesenses and which adjoin one another in a turning point, the turningpoints of the outer ball tracks are positioned in a track plane at adistance from the center plane towards the aperture end, and wherein theturning points of the inner ball tracks are positioned in a track planeat a distance from the center plane towards the aperture end, theturning points are each positioned below a maximum of the distancebetween the center lines and the parallel axes.
 70. A constant velocityjoint according to claim 64 wherein for the second pairs of tracks; thetrack center lines of the outer ball tracks comprise a first arch with aradius (R1) whose center in the track plane is offset by a first axialoffset (O1 a) from the center plane (EM) of the joint towards theattaching end and by a first radial offset (O1 r) from the parallel axistowards the ball track and, in the region adjoining said arch, towardsthe attaching end, they comprise a second arch with the radius (R2)whose center in the track plane is offset by a second axial offset (O2a) from the center plane of the joint towards the aperture end and isoutwardly offset from the parallel axis by a second radial offset (O2 r)which is greater than the sum of the first arch radius (R1) and thefirst radial offset (O1 r), and the track center lines of the inner balltracks comprise a first arch with a radius (R1′) whose center in a trackplane is offset by a first axial offset (O1 a′) from the center plane ofthe joint towards the aperture end and by a first radial offset (O1 r′)from the parallel axis towards the ball track and, in the regionadjoining said arch, towards the aperture end, they comprise a secondarch with a radius (R2′) whose center in the track plane is offset by asecond axial offset (O2 a′) from the center plane of the joint towardsthe attaching end and is outwardly offset from the parallel axis by asecond radial offset (O2 r′) which is greater than the sum of the firstarch radius (R1′) and the first radial offset (O1 r′).
 71. A constantvelocity joint according to claim 64 wherein for the second pairs oftracks: the radius of curvature of the center lines of the outer balltracks decreases in its extension from the center plane towards theattaching end and the radius of curvature of the center line of theinner ball tracks decreases in its extension from the center plane tothe aperture end.
 72. A constant velocity Joint according to claim 70wherein for the second pairs of tracks: the radius of curvature of thecenter lines of the outer ball tracks decreases in its extension fromthe center plane towards the attaching end and the radius of curvatureof the center line of the inner ball tracks decreases in its extensionfrom the center plane to the aperture end.
 73. A constant velocity jointaccording to claim 72 wherein for the second pairs of tracks: the trackcenter lines of the outer ball tracks comprise a third arch with aradius (R3) which tangentially, while having the same sense ofcurvature, adjoins the first arch and whose radius (R3) is smaller thanthe first arch radius (R1), and the track center lines of the inner balltracks comprise a third arch with a radius (R3′) which tangentially,while having the same sense of curvature, adjoins the first arch andwhose radius (R3′) is smaller than the first arch radius (R1′).
 74. Ajoint according to claim 70 wherein, in the second pairs of tracks,along the extension of the center line of the outer ball tracks, towardsthe aperture end, the second arch (R2) is adjoined by an axis-parallelstraight line (G3) and wherein, along the extension of the center lineof the inner ball tracks, the second arch (R2′), towards the attachingend, is adjoined by an axis-parallel straight line (G3′).
 75. A jointaccording to claim 70 wherein, in the second pairs of tracks, along theextension of the center line of the outer ball tracks, towards theaperture end, the second arch (R2) is adjoined by a straight line whichapproaches the parallel axis, and wherein along the extension of thecenter line of the inner ball tracks, the second arch (R2′), towards theattaching end, is adjoined by a straight line which approaches theparallel axis.
 76. A joint according to claim 64 wherein, in the secondpairs of tracks, the center lines of the ball tracks in the joint centerplane Intersect one another at an angle of 4 to 32°, and whereintangents at the center lines of the ball tracks of all pairs of tracksform identical opening angles (α) when the joint is aligned.
 77. Aconstant velocity fixed joint comprising: an outer joint part whichcomprises a first longitudinal axis and an attaching end and an apertureend arranged so as to be axially opposite one another, and outer balltracks; an inner joint part which comprises a second longitudinal axisand an attachment for a shaft pointing towards the aperture end of theouter joint part, and inner ball tracks, the outer ball tracks and theinner ball tracks form pairs of tracks with one another which eachaccommodate a torque transmitting ball; an annular ball cage between theouter joint part and the inner joint part and comprisingcircumferentially distributed cage windows which each accommodate atleast one of the torque transmitting balls, the centers of the balls areheld by the cage in a joint center plane and, upon articulation of thejoint, are guided onto the angle-bisecting plane between the first andsecond longitudinal axes, wherein center lines of adjoining ball tracks,in the outer joint part are positioned in pairs of first track planeswhich extend parallel relative to one another and symmetrically relativeto radial rays through the joint center, wherein the center lines ofadjoining ball tracks in the inner joint part are positioned in pairs ofsecond track planes which extend parallel relative to one another andsymmetrically relative to radial rays through the joint center, thefirst track planes and the second track planes, together with radialplanes through the first and second longitudinal axes, form identicallysized angles (γ, γ′) which extend in opposite directions, for firstpairs of tracks, a first opening angle (α₁) between tangents at trackbase lines extending parallel to tangents at the center lines of theball tracks in the joint center plane when the joint is aligned withcoinciding longitudinal axes, opens from the attaching end to theaperture end, for second pairs of tracks, a second opening angle (α₂)between tangents at track base lines extending parallel to tangents atthe center lines of the ball tracks in the joint center plane when thejoint is aligned with coinciding longitudinal axes, opens from theaperture end to the attaching end, and for the center lines of thesecond pairs of tracks: in the outer joint part, the center line of theball tracks in a region from the joint center plane to the attaching endradially inwardly departs a first reference radius centered in a pointof intersection of a perpendicular line on a tangent at the center lineof the ball track in the joint center plane and of a first referenceaxis through a track plane; in the inner joint part the center line ofthe ball tracks in a region from the joint center plane to the apertureend radially inwardly departs a second reference radius centred in apoint of intersection of a perpendicular line on a tangent at the centerline of the ball track in the joint center plane and a second referenceaxis through a track plane; in the outer joint part, the center line ofthe ball tracks in the region from the joint center plane to theaperture end moves radially outwardly beyond said first referenceradius; and in the inner joint part, the center line of the ball tracksin the region from the joint center plane to the attaching end movesradially outwardly beyond said second reference radius.
 78. A constantvelocity joint according to claim 77 wherein for the second pairs oftracks: in the outer joint part, a first local radius (R1) of curvatureof the center line in the joint center plane is smaller than the firstreference radius, in the inner joint part, a second local radius (R1′)of curvature of the center line in the joint center plane is smallerthan the second reference radius.
 79. A constant velocity jointaccording to claim 77 wherein for the second pairs of tracks: in theouter joint part, the center line of the ball tracks extends from thejoint center plane towards the attaching end radially outside a thirdreference radius (RZ) whose radius center is positioned in the jointcenter plane on one of the reference axes, and in the inner joint part,the center line of the ball tracks extends from the joint center planeto the aperture end radially outside a fourth reference radius (RZ′)whose radius center is positioned in the joint center plane on one ofthe reference axes.
 80. A joint according to claim 77 wherein for thesecond pairs of tracks: in the outer joint part, the center line of theball tracks extends from the joint center plane to the aperture endradially outside the first reference radius, and in the inner jointpart, the center line of the ball tracks extends from the joint centerplane to the attaching end radially outside the second reference radius.81. A constant velocity joint according to claim 77 wherein for thesecond pairs of tracks: in the outer joint part, the center line of theball tracks extends from the joint center plane to the aperture endradially inside a third reference radius (RZ) whose radius center ispositioned in the joint center plane on one of the reference axes, andin the inner joint part, the center line of the ball tracks extends fromthe joint center plane to the attaching end radially inside a fourthreference radius (RZ′) whose radius center is positioned in the jointcenter plane on one of the reference axes.
 82. A constant velocity jointaccording to claim 77 wherein for the second pairs of tracks: the centerlines of the outer ball tracks and inner ball tracks each comprise atleast two arched portions which are curved in opposite senses and whichadjoin one another in a turning point, the turning points of the outerball tracks are positioned in a track plane at a distance from thecenter plane towards the aperture end, the turning points of the innerball tracks are positioned in a track plane at a distance from thecenter plane towards the aperture end, the turning points are eachpositioned below a maximum of the distance between the center lines andthe reference axes.
 83. A constant velocity joint according to claim 77wherein for the second pairs of tracks; the track center lines of theouter ball tracks comprise a first arch with a radius (R1) whose centerin a track plane is offset by a first axial offset (O1 a) from thecenter plane of the joint towards the attaching end and by a firstradial offset (O1 r) from the first reference axis towards the balltrack and, in the region adjoining said arch, towards the attaching end,they comprise a second arch with a radius (R2) whose center in the trackplane is offset by a second axial offset (O2 a) from the center plane ofthe joint towards the aperture end and is outwardly offset from thefirst reference axis by a second radial offset (O2 r) which is greaterthan the sum of the first arch radius (R1) and the first radial offset(O1 r), and the track center lines of the outer ball tracks comprise afirst arch with a radius (R1′) whose center (M1′) in a track plane isoffset by a first axial offset (O1 a′) from the center plane of thejoint towards the aperture end and by a first radial offset (O1 r′) fromthe second reference axis towards the ball track and, in the regionadjoining said arch, towards the aperture end, they comprise a secondarch with a radius (R2′) whose center in the track plane is offset by asecond axial offset (O2 a′) from the center plane of the joint towardsthe attaching end and is outwardly offset from the second reference axisby a second radial offset (O2 r′) which is greater than the sum of thefirst arch radius (R1′) and the first radial offset (O1 r′).
 84. Aconstant velocity joint according to claim 77 wherein for the secondpairs of tracks: the radius of curvature of the center lines of theouter ball tracks decreases in its extension from the center planetowards the attaching end and the radius of curvature of the center lineof the inner ball tracks decreases in its extension from the centerplane to the aperture end.
 85. A constant velocity joint according toclaim 83 wherein for the second pairs of tracks: the radius of curvatureof the center lines of the outer ball tracks decreases in its extensionfrom the center plane towards the attaching end and the radius ofcurvature of the center line of the inner ball tracks decreases in itsextension from the center plane to the aperture end.
 86. A constantvelocity joint according to claim 85 wherein for the second pairs oftracks: the track center lines of the outer ball tracks comprise a thirdarch with a radius (R3) which, tangentially, while having the same senseof curvature, adjoins the first arch and whose radius (R3) is smallerthan the first arch radius (R1), and the track center lines of the innerball tracks comprise a third arch with a radius (R3′) which,tangentially, while having the same sense of curvature, adjoins thefirst arch and whose radius (R3′) is smaller than the first arch radius(R1′).
 87. A joint according to claim 83 wherein, in the second pairs oftracks, along the extension of the center line of the outer ball tracks,towards the aperture end, the second arch (R2) is adjoined by a straightline (G3) extending parallel to the first reference axis and wherein,along the extension of the center line of the inner ball tracks, thesecond arch (R2′),towards the attaching end, is adjoined by a straightline (G3′) extending parallel to the second reference axis.
 88. A jointaccording to claim 83 wherein, in the second pairs of tracks along theextension of the center line of the outer ball tracks, towards theaperture end, the second arch (R2) is adjoined by a straight line whichapproaches the reference axis and wherein along the extension of thecenter line of the inner ball tracks, the second arch (R2′), towards theattaching end, is adjoined by a straight line which approaches thesecond reference axis.
 89. A joint according to claim 77 wherein, in thesecond pairs of tracks, the center lines of the ball tracks in the jointcenter plane intersect one another at an angle of 4° to 32°, and whereintangents at the center lines of the ball tracks of all pairs of tracksform identical opening angles (α) when the joint is aligned.
 90. Aconstant velocity joint according to claim 77 wherein a radial distanceof penetration points (D₁, D₂) of tangents at the track center linesextending through the radial planes (R1, R2) from the longitudinal axes(L12, L13) is smaller than a pitch circle radius of the balls in thejoint.
 91. A constant velocity joint according to claim 90 wherein saidradial distance of penetration points equals zero.
 92. A joint accordingto claim 64 wherein the number of the pairs of tracks can be divided byfour.
 93. A joint according to claim 77 wherein the number of the pairsof tracks can be divided by four.
 94. A joint according to claim 64wherein the balls of two adjoining pairs of tracks positioned inparallel track planes are received by one single cage window of the ballcage.
 95. A joint according to claim 77 wherein the balls of twoadjoining pairs of tracks positioned in parallel track planes arereceived by one single cage window of the ball cage.
 96. A Jointaccording to claim 64 wherein a pitch angle (2φ) between pairs of trackswhose balls are received in a common window is smaller than a pitchangle between adjoining pairs of tracks whose balls are received indifferent adjoining windows.
 97. A joint according to claim 77 wherein apitch angle (2φ) between pairs of tracks whose balls are received in acommon window is smaller than a pitch angle between adjoining pairs oftracks whose balls are received in different adjoining windows.
 98. Aconstant velocity joint according to claim 64 wherein, of two directlyadjoining pairs of tracks, one constitutes a first pair of tracks andone a second pair of tracks.
 99. A constant velocity joint according toclaim 77 wherein, of two directly adjoining pairs of tracks, oneconstitutes a first pair of tracks and one a second pair of tracks. 100.A constant velocity joint according to claim 64 wherein, of two pairs oftracks positioned in one track plane, one constitutes a first pair oftracks and one a second pair of tracks.
 101. A constant velocity jointaccording to claim 77 wherein, of two pairs of tracks positioned in onetrack plane, one constitutes a first pair of tracks and one a secondpair of tracks.